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Iapetus Simulation
This is a simulation of what one would expect to find on a terraformed Iapetus, using formulas from Math And Terraforming. Please note that not even the supercomputers at NASA can provide us with a perfect simulation. The information showed here is only an approximation. Basic data *Distance from Sun: 1453.53 million km *Distance from Saturn: 3.261 million km *Diameter: 1469 km *Solar Constant: 0.0209 *Mass: 0.0003023 Earths *Mean density: 1.088 kg/l *Saturn's period: 29.457 Earth years *Day length: 79.3215 Earth days *Rotation axial tilt: 17 degrees Atmosphere See Atmosphere Parameters Given the very low gravity, it will be difficult for Iapetus to hold an atmosphere. During this simulation, we will use an atmosphere with the same pressure at sea level as Earth's and a similar composition. *Atmosphere stability for oxygen molecules: **Earth's gravity (15 degrees C): 4.116 **Iapetus's gravity (15 degrees C): 78.1 **Iapetus's gravity (-150 degrees C): 33.37 *Atmosphere stability for water molecules: **Earth's gravity (15 degrees C): 7.320 **Iapetus's gravity (15 degrees C): 138.8 **Iapetus's gravity (-150 degrees C): 59.32 *Atmosphere stability for hydrogen molecules: **Earth's gravity (15 degrees C): 65.88 **Iapetus's gravity (15 degrees C): 1249 **Iapetus's gravity (-150 degrees C): 533.9 notes: A value below 10 means stability for over a million years, a value between 10 and 100 means stability between 0.1 and 10 millions of years, while a value higher then 100 means stability for less then 10 thousand years. This calculation does not include solar wind erosion. Conclusion: The atmosphere of Iapetus will be divided in two distinct layers, separated by a greenhouse gas buffer. In the upper layer, where temperature will be low, oxygen and nitrogen can be held for thousands of years. However, water vapors, if they make their way that far, will be lost into space. In the lower layer, even oxygen is nearly unstable. Water vapors will fast rise to the upper layer. Hydrogen, resulting from interaction between water molecules and ionizing radiation, will escape into space very fast. And since Iapetus lies most of time outside of Saturn's magnetosphere, the effects will be dramatic. The atmosphere will look like this: Ground average temperature: 15 degrees C *Surface pressure at sea level: 1 *Atmosphere total mass (Earth = 1): 0.98 *Atmosphere breathable height: 385 km *Atmosphere total height: 1146 km Ground average temperature: -150 degrees C *Surface pressure at sea level: 1 *Atmosphere total mass (Earth = 1): 0.60 *Atmosphere breathable height: 269 km *Atmosphere total height: 800 km Combined values *Atmosphere total mass (Earth = 1): 0.79 *Atmosphere breathable height: 330 km *Atmosphere total height: 1000 km. As one can see, Iapetus will have a very fluffy atmosphere, rising higher then a moon radius. At that height, gravity is reduced to 50%, so the atmosphere will actually be even higher. If the atmosphere height rises to one moon diameter, the moon will not be able to hold it, because at that height gravity is reduced to one fourth. So, Iapetus is close to the limit where an atmosphere will be unstable for a hundred Earth years. Temperature Main article: Temperature. The first problem with Iapetus is that we need to gain the correct surface temperature. The Solar Constant is small (0.0209), compared to Earth (1.98). We will need Greenhouse Gases. The Greenhouse Calculator shows us that Titan will need 0.656 kg/sqm of sulfur hexafluoride. Climate Simulation Main article: Climate. On Earth, the average temperature is +15 degrees C. Technicians will try, with the help of greenhouse gases, to keep this temperature. Iapetus has a smaller diameter then Earth (0.115), so air currents can mix temperatures faster. The atmosphere will be high enough to pass over all Geographic barriers. Average temperatures for each latitude: At equinox: *poles: 15.0 C *75 deg: 15.2 C *60 deg: 15.3 C *45 deg: 15.3 C *30 deg: 15.3 C *15 deg: 15.4 C *equator: 15.4 C At winter solstice: *poles: 15.0 C *75 deg: 15.0 C *60 deg: 15.1 C *45 deg: 15.2 C *30 deg: 15.3 C *15 deg: 15.3 C *equator: 15.4 C At summer solstice: *poles: 15.3 C *75 deg: 15.3 C *60 deg: 15.4 C *45 deg: 15.4 C *30 deg: 15.4 C *15 deg: 15.4 C *equator: 15.4 C Day - night cycle variation: Iapetus has a very long day (79.3215 Earth days), but is well protected by its greenhouse layer. So, temperature variations between day and night will not be significant. *Daily temperature variation: 1 degrees C *Equator day-night variations: **Equinox: 14.4 to 15.4 degrees C **Solstice: 14..4 to 15.4 degrees C *Day - night variations for 45 deg latitude: **Equinox: 14.3 to 15.3 degrees C **Winter solstice: 14.2 to 15.2 degrees C **Summer solstice: 14.4 to 15.4 degrees C Seasons: Iapetus has its axis tilted with respect to the Sun. However, because of the very strong greenhouse effect, this will result in temperature variations of only one degree C. Altitude variations: Iapetus has a huge equatorial mountain range. However, because atmosphere pressure will not decrease significantly below the greenhouse gas layer, temperature on the highest mountains will only be with one or two degrees lower then on the surface. Conclusion. Iapetus is a challenging little Outer Planet. Its climate pattern is a monoclime, with temperature barely changing around the value of 15 degrees C. In such conditions, winds will be very slow, because there will be almost no pressure differences between masses of air. In such conditions, water will accumulate in the atmosphere up to saturation level. The low gravity has a side effect. At surface, speed of water molecules in the atmosphere can on rare occasions reach the escape velocity (this is why we have such a high value, 138). As a result, all the lower atmosphere will get saturated fast with water. Condensation will occur, as clouds and fog will form. However, because of the little gravity, rain droplets will move much slower through the atmosphere and can grow much larger then on Earth. Iapetus will be an unhealthy, wet environment. Geography See also: Geography, Geographic Pattern - Tectonic and Geographic Pattern - Craters. Iapetus has a very low density, a thing that suggests it is made almost entirely of water ice. It is questionable what will remain solid if we melt the ice and how much time will be needed to produce so much heat. It will require very much time. Terraformers have 3 major ways to transform an icy Outer Planet: #Increase the heat, melt the ice and transform it into an Oceanic Planet, then leave it as it is. #If possible, build Artificial Continents after melting all the ice. #Use Ground Insulation, to save the icy crust, then cover it with solid rock. However, for Iapetus, another option might be possible. The moon will melt its crust very slow, about 5.6 m in an Earth year (see Adjusting Temperature for details). In a Saturn year (29 Earth years), we will only melt 162 m in this way. However, by removing that amount of ice, solid particles that once were trapped in the ice will remain behind and form an insulation crust, lowering the process. Temperature will start to rise and melting will slow down. If this option is token into consideration, Iapetus will hold most of its Geological features nearly intact. It is just like on Earth when snow melts and dirt in the snow remains on surface, but here it will be on a far larger scale. Melted water will flow to depressions, where it will form lakes and ponds. Because water is heavier then ice, in time, lakes will melt the ice at their bottom and water will flow down into the crust. This will continue until a state of equilibrium is reached, when a natural insulation process will slow down the process considerably. After a Saturnian year, melting process will reduce from 5.6 m/Earth year to probably a few cm. Mountains: Iapetus has a large mountain range that rises up to 18 km and nearly encircles the moon. This massive structure will not be eroded fast. Given the fluffy atmosphere that Iapetus will have, the effects on air circulation will be like of a 500 m high mountain range on Earth. So, climate will not be different. As ice will slowly melt, it will form valleys into the mountain range, that will look similar to valleys on Earth. In that place, there will always be exposed ice that will continue to melt, feeding rivers. Surrounding the mountain range, there will form lakes deposits of sediments. It will be the most interesting place on Iapetus. There are also many other elevated structures on Iapetus, like crater rims, which will act very similar, but on a smaller scale. Depressions: Melted water will flow into depressions, creating lakes. There, it will exchange temperature with the water beneath, melting it. Lakes will slowly find their way down, through cracks in the crust, vanishing from surface. At the same time, sedimentation will occur. Rocks and dust from the ice will be transported to depressions, where they will form the basis of a new soil. If enough soil is deposited above the ice, it will act like an insulation. Less ice will be melt beneath each lake and less water will escape underground. However, at the same time, as ground becomes covered with solid materials, less water will melt to feed the lakes. So, it is unknown on a longer timescale if lakes will increase or decrease in size. Conclusion: Iapetus will be a dynamic world, if this method of terraforming is selected. The melting process will never stop completely, it will only be slowed down. On a long timescale, processes like landslides or the collapse of ice caves can occur. High terrain will get slowly eroded, creating vast networks of rivers. Lakes will form, increase in size or vanish. The Sky As any Outer Planet, Iapetus will have a lot of moisture in its atmosphere. Because of this, fogs and clouds will be common. Probably the atmosphere will never be clean enough to see even a corner of blue sky. Still, from orbit, some celestial bodies will be visible. The Sun will appear 0.97 units wide (like an object 0.97 mm wide will appear if you look from a distance of 1 m, see Angular Size for details). Saturn and other satellites visible as disks will be: *Saturn - 32.71 units *Tethys - star to 0.33 units *Dione - star to 0.35 units *Rhea - 0.37 to 0.53 units *Titan - 1.07 to 2.20 units Some planets will also be visible: *Mercury: 4.6 to 4.8 *Venus: 1.7 to 2.0 *Earth: 2.9 to 3.4 *Mars: 5.9 to >6 *Jupiter: -0.2 to 2.4 However, people from the surface will not see this, unless they fly into outer space. Human Colonies *Population limit: 0.71 million *Land population feeding capacity: 3.3 people fed from one square km *Largest city supported by environment: 2 800 people Assuming it will have similar types of terrain Earth will have, Titan can support a Population Limit of 0.71 million people. An outer planet is in a critical balance. An increase of heat form the surface can result in a hole in the greenhouse layer. This is why population limit is calculated to be so small. If the biosphere of Iapetus will only be able to support 710000 people, one might ask if terraforming is actually feasible (see Where terraforming is impossible for more details). Industry Iapetus is made of water ice, with little amounts of other compounds. It is questionable if it contains valuable minerals and what kind of industry might develop here. The main source of energy should be nuclear. Air currents are too slow and rivers, with so little gravity, will not be able to generate much energy. Agriculture There is a lack of light on Iapetus, that will limit plant life (see Plants on new worlds for details). Agriculture is still possible, but large surfaces will need to be planted to feed the population. Clouds will further reduce luminosity. Not many plants will adapt to this wet environment. Transportation With little gravity, air transport will be efficient and used on large scale. This will be the best way to move people and cargo. Roads and railways are possible, but because of the low gravity, vehicles will have little inertia and will tend to lose contact with surface. Water transportation is out of question. Gravity is small and a person weighting 70 kg on Earth, on Iapetus will only weight 1.6 kg. In such conditions, people will be able to fly with artificial wings. Since Iapetus is tidal locked, there is no place for geosynchronous satellites. Still, there are many safe orbits around the moon for satellites that will provide telecommunications. The large atmosphere will pose major challenges for radio waves. There will be constructed at least one base on the surface, for space travel. Large interplanetary ships, carrying passengers and cargo to and from Saturn, will dock at Helene. Then, smaller ships will ferry between the little moon Helene and Iapetus. Tourism With so much moisture, visibility will be reduced. Even if the mountain range is spectacular, people will be unable to see it. Still, there is a chance tourism will exist on Iapetus. As ice will melt, it will release minerals and gasses trapped inside. This will lead in some places to formation of mineral springs, that can be used to treat diseases. Wild Life What kind of life will like the wet conditions of Iapetus? There are many species of algae and lichens, as well as other kinds of swamp vegetation that will adapt easy. As for animals, reptiles, frogs, worms and some insects will adapt very easy. Category:Simulation Category:Math